SonexBuilders.net

One thing I havnt figured out, perhaps you guy's can help. With the Dial a Trim setup, do you still keep the "bungee rubber".
Thanks

I should have added, the bungee rubber shown on the plans to take the weight of the elevator.

No, you just have the two springs. One is static, the other is dynamic controlled by the DialATrim. Set it up to the instructions then adjust the bias based on your flight testing.

Anybody able to get the dial a trim to work for both solo and gross weight. If I set it up the rear spring for gross weight I have just enough nose down trim before running out of dial but when I fly it solo I run out of nose up dial when setting up to land. If I adjust the rear spring the other way for solo flight I'm good when setting up to land but have to hold alot of forward stick when I get to gross weight. I'm a bit dissapointed in the system as it seems there isn't enough travel in the dial no matter where the rear spring is set.

kmacht wrote:Anybody able to get the dial a trim to work for both solo and gross weight. If I set it up the rear spring for gross weight I have just enough nose down trim before running out of dial but when I fly it solo I run out of nose up dial when setting up to land. If I adjust the rear spring the other way for solo flight I'm good when setting up to land but have to hold alot of forward stick when I get to gross weight. I'm a bit dissapointed in the system as it seems there isn't enough travel in the dial no matter where the rear spring is set.

Nope, thats why I replaced mine with an electric trim system that will handle an infinite range. Same idea, a static spring and a dynamic. the dynamic is attached to a 12V motor spool via a cable that winds up or spools out based on a DPDT switch on my stick. Use a similar system for a wing leveler.

This is a good discussion, I am interested in hearing more opinions. I am about to start cutting in my panel and currently have the hardware for both the manual trim and the dial-a-trim. Based on this thread, I may go back to the original plans.

I'm getting in on the discussion for a moment but coming from a different platform. With the Waiex, and aerodynamic trim tab is out of the question. No way to have a movable tab on two ruddervators. I rely totally on spring pressure for trim fore and aft. With the Dial a trim, I have my Waiex set to have climb trim at take off climbout speed (115mph) at just 2 turns off of full up trim with solo weight and full tank. At pattern altitude, I normally turn it one full turn down and pick up the climb speed to 120-125mph indicated.
While cruising and burning off fuel it takes very small changes with fuel burn. If I get down in the 4 gallon left range I'm normally within 2 turns of being full down trim.
Two up and max weight (1,200lbs) is another story. Takeoff with 5 turns down from full up trim. Work my way down to full down trim by 7 gallons left in the tank and then its a pain in the butt. You fly with down pressure and on landing with 2 notches of flaps out of three, it requires virtually no flare. You just fly it into ground effect and wait. The plane will 3 pt with no up pitch movement. Basically your at the rear CG. Not a problem if you understand and fly the plane with this always in the forefront of your brain. Pitch movements need to be smooth and gentle to avoid PIO. Anyone that's ever flown a 206 tail heavy gets the picture.
As far as up trim in the pattern. Well that's a problem. I go to full up trim at power reduction on the downwind and fly my base at about 75 unless there is a reason to go faster (big airport) and try to cross the numbers at about 60 indicated. There never has been enough up trim on landing. You just do the arm strong method.
I suspect the conventional tail maybe does a bit better in the trim regard on landing, especially if it has the movable tab. Anyone care to comment on that last part?

Larry
Waiex121YX

I would leave the manual trim ,I jflown both and much rather have the manual trim with the small lever on the left side. That's also what my Sonex has and works great
Adam Simmons

A bellcrank used to increase the throw at the spring may work. For my Waiex I bought a Dial-A-Trim but it is still in the shrink wrap.

I have flown both a waiex and sonex with Dial A Trim. The system does work. Its rather challenging to find the sweet spot on the spring bias, you tend to reach the end of range on the knob before you are trimmed. I'm sure with enough tweeking you can find a setting that gives you full trim control through the entire W/B range. Its not a bad system.